Paint mixer



Aug. 4, 1959 P. J. O'NEILL, JR 2,898,094

PAINT MIXER Filed Jan. 16. 1956 III INVENTOR,

PAUL J 07VE/LL,J. BY

ATTORNEYS.

United States Patent 4 PAINT MIXER Paul J. ONeill, Jr., San Francisco, Calif., assignor to Union Machine Company, San Francisco, Calif., a corporation of California Application January 16, 1956, Serial No. 559,487

6 Claims. or. 259-116) This invention relates to apparatus for mixing or agitating paint, or other liquids.

Paint mixers in the past have been subject to several disadvantages. In some cases, the mixers have been able to bring about fairly complete uniformity only after a substantial period of operation. The inadequacy was due largely to the fact that actual agitation or mixing was localized in the body of paint. Flow of paint to the localized mixing space was not well defined, and a considerable period of time was therefore required in order that the entire contents of the container be acted upon by the agitator or mixer.

The object of the present invention is to overcome these disadvantages, and provide a simple agitator or mixer structure that ensures complete mixing or agitating of the paint in a short period of time. To accomplish this purpose, the apparatus causes substantially the entire mass of paint to move in a well defined flow path, and mixing takes place throughout substantially the entire volume of the container.

Another object of this invention is to provide apparatus of this character adapted for operation by hand, and that requires little effort for operation. 7

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of one embodiment of the invention. For this purpose, there is shown a form in the drawings accompanying and forming a part of the present specification. This form will now be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of this invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a longitudinal sectional view of a mixer structure incorporating the present invention, the full and phantom line positions illustrating extreme positions of the mechanism;

Fig. 2 is a longitudinal sectional view, similar to Fig. 1, but showing an intermediate position of the mechanism; and

Figs. 3 and 4 are sectional views taken along planes indicated by lines 33 and 44 of Figs. 1 and 2, respectively.

In Fig. 1 a can contains therein a body of liquid or paint 11 that is intended to be mixed by the mixer structure 12. The mixer structure provides a cover 13 having a depending flange 14 overlying the usual beaded edge 15 of the paint can 10.

One or morepaddles or impeller disks 16 and 17 are supported in spaced relationship along the length of a shaft 18 and form the operative elements of the mixer.

The shaft 18 is mounted so as to permit movement of the disks 16 and 17 and the shaft along the axis 19 of the shaft 18. When the paddles or disks 16 and 17 are moved downwardly, an endless flow pattern is created by the motion, as indicated by the arrows 20. When the 2,898,094 Patented Aug. 4, 1959 disks 16 and 17 are so moved, the paint near the center of the can is urged downwardly and the paint near the periphery of the can 10 is displaced upwardly. The area of each disk is preferably at least half that of the circular area of the can so that the flow rate of the paint upwardly near the periphery of the can is substantial, thereby ensuring effective mixing. 7

Each of the disks includes a central hub portion 21 and 22 secured to the shaft 18 as by welding.

In order to permit reciprocatory movement of the shaft 18 with its paddles 16 and 17, the shaft 18 is piloted in a central boss 23 of the cover 13.

The shaft reciprocates along axis 19 upon rotation of the shaft. For this purpose, the outer surface 24 of the boss 23 extends helically throughout 360, there being a vertical wall 26 joining the crest or uppermost portion of the boss surface 24 with the lowermost portion thereof. A following pin 25, extending laterally of the projecting end of the shaft 18 and attached thereto, cooperates. with this surface Accordingly, as the shaft 18 is rotated and the pin 25 maintained in engagement with the surface 24, the shaft 18 is raised gradually, and then permitted suddenly to fall as it passes over the crest of the surface 24.

In order to rotate the shaft 18, a driving member 27 is provided. The driving member 27 has a hollow cylindrical extension 28 telescoping over the boss 23. The end of the extension and a flange 30 formed at the end of the extension fit in a shallow recess 40 formed between the boss 23 and an annular land 41 of the cover 13. A ring 29 detachably secured to the land 41, as by cap screws 42, overlies the flange 30 to retain the driving member in position. The driving member 27 is accordingly rotatably mounted about the axis of the device. The outer end of the shaft 18 projects with clearance partially into an axial bore 31 of the driving member 27.

The extension 28 of the driving member 27 has an elongate slot 43 in which the outer end of the pin 25 is received. Accordingly, the member 27 is coupled in driving relationship to the impeller shaft 18. Thus, upon rotation of the driving member 27, rotation is imparted to the shaft 18, the elongate slot 43 maintaining a driving connection for any longitudinal position of the shaft.

For rotating the driving member 27, a handle 32 is provided'that has a socket 33 receiving the reduced end of the driving member 27. A compression spring 34 extending into the bore 31 engages the end of the shaft 18 and the bottom of the socket 33 to urge the shaft 18 in a direction corresponding to engagement of the pin 25 with the helical surface 24 of the boss 23.

During rotation of the shaft 18, the spring 34 is compressed until the pin 25 is at the crest of the boss surface 24, as shown in the full-line position of Fig. 1. Upon further slight angular movement, the pin 25 clears the crest of the surface 24, and the energy stored in the compression spring urges the shaft quickly downwardly along the vertical shoulder 26. Substantial downward movement of the paddles 16 and 17 sets up the flow of material in the can 10, as previously described. The phantom-line position in Fig. 1 illustrates the position of the paddles 16 and 17 and shaft 18 when the pin 25 engages the lowermost portion of the helical surface 24.

In Fig. 2 the paddles. 16 and 17 are at an intermediate positon, the driving member 27 having been rotated onehalf of a revolution from the position shown in Fig. 1.

In order to achieve maximum movement and mixing of the material per unit of time, the flow path indicated by the arrows 20 is unidirectional. Upward movement of the paddles or disks 16 and 17 is substantially ineffective to reverse the flow. For this purpose, a series of blades 35 and 36 are struck upwardly from the disks 16 and 17. The blades 35 and 36, four in number in this 2,898,094 U p a instance for each disk, extend radially inwardly from the periphery of the disks 16 and 17 to points spaced slightly from the hubs of the respective disks. The pitch of the blades 35 and 36 corresponds in direction to that of the helix formed by the boss surface 24. The blades scoop the material from the upper side of the disks to the lower sides thereof upon rotation of the shaft in the appropriate direction. The blades are so designed as to transfer liquid to the lower side of the disks at rates substantially equal to the volumetric displacement of the area of each of the paddles during upward travel of the shaft 18. Accordingly, during upward movement of the shaft 18, the paint is relatively undisturbed and upward movement of the paddles is relatively unrestrained.

The blades 35 and 36 projected into the plane of the disks substantially overlie the cut from which the blades are formed. Accordingly, when the disks 16 and 17 move quickly downwardly under the influence of the spring 34, the disks act substantially as though the blades did not exist. Accordingly, downward movement of the disks sets up the flow pattern indicated.

Upon continuous rotation of the apparatus, a rapid intermittent movement of the material takes place, and the material is effectively mixed in a short period of time.

Other forms of impeller elements could be provided. Instead of being of disk form, the elements could be formed as helical vanes extending at least one revolution, for example.

The inventor claims:

1. In a mixer structure: a base adapted to cover a container opening, and having a boss, the end surface of the boss extending helically about the axis of the boss, there being a shoulder joining the crest and trough of the surface; a shaft guided in the boss; a pin carried by the shaft and projecting laterally thereof for engagement with said end surface, said pin extending radially beyond the boss; a rotary driving member movable about the axis of the boss, and having a hollow part extending over the boss, the driving member having a bore receiving the end of the shaft; said hollow part having an elongate slot in which the end of the pin is received for coupling the driving member and the shaft; resilient means urging the shaft in an axial direction corresponding to engagement between the pin and said end surface; and a handle for rotating the driving member.

2. In a mixer structure: a base adapted to cover a container opening, and having a boss, the end surface of the boss extending helically about the axis of the boss, there being a shoulder joining the crest and trough of the surface; a shaft guided in the boss; a pin carried by the shaft and projecting laterally thereof for engagement with said end surface, said pin extending radially beyond the boss; a rotary driving member movable about the axis of the boss, and having a hollow part extending over the boss, the driving member having a bore receiving the end of the shaft; said hollow part having an elongate slot in which the end of the pin is received for coupling the driving member and the shaft; resilient means urging the shaft in an axial direction corresponding to engagement between the pin and said end surface; a handle for rotating the driving member; and a paddle carried by the shaft; said paddle having a series of vanes defining flow paths transversely through the paddles, the vanes being inclined in a direction corresponding to the helical surface to permit movement of the paddle only in one axial direction without displacement of the material in the container.

3. In a mixer structure: a base forming a container cover and having a boss, the end surface of which extends helically about the axis of the boss, there being a shoulder forming the crest and trough of the surface; a shaft guided in the boss; a pin carried by the shaft and engaging the surface; rotary driving means positively coupled to the 4 shaft so that the angular movement of the shaft bears a fixed ratio to the angular movement of said rotary driving means; energy storing means urging the shaft in a direction corresponding to engagement of the pin and the surface; said shaft being mounted for axial movement in response to the movement of said pin over said surface; and an impeller carried by the shaft.

4. In a mixer: an impeller having one or more through passages; rotary driving means positively coupled to said impeller. for imparting angular movement .to said im. peller and so that angular movement of the impeller bears a fixed ratio to the angularmovement of said rotary driving means; means effective to move the impeller gradually in one axial direction through the liquid while the angular movement is imparted to the impeller and so that axial movement of said impeller in said one direction is in direct fixed proportion to the angular movement of said impeller; and means for suddenly moving theimpeller in the opposite axial direction after predetermined movement of said impeller in said one axial direction; said impeller having means operative by angular movement thereof for transferring liquid from one side of the impeller to the other and at a rate corresponding substantially to the volumetric displacement of said impeller during axial movement thereof in said one direction and whereby no net movement of the liquid results upon axial movement of said impeller in said one axial direction.

5. In a mixer cooperable with a container having an opening: a support adapted to be secured to the container; a shaft carried by the support; an impeller carried by the shaft; and mechanism for rotating the impeller relative to the support while causing the impeller gradually to move axially in one direction relative to the support and for suddenly moving the impeller axially in the other direction upon predetermined rotation of the impeller; said mechanism including rotary driving means positively coupled to the impeller so that angular move ment of said impeller is in direct fixed proportion to the angular movement of said rotary driving means; the impeller having vane means inclined only in one direction for permitting passage of fluid past the impeller and for substantially reducing viscous drag on the impeller as the impeller is moved in said one direction.

6. In a mixer cooperable with a container having an opening: a support adapted to be secured to the container; a shaft carried by the support; an impeller carried by the shaft; and mechanism for rotating the impeller relative to the support while causing the impeller gradually to move axially in one direction relative to the support and for suddenly moving the impeller axially in the other direction upon predetermined rotation of the impeller; said mechanism including rotary driving means positively coupled to the impeller so that angular movement of said impeller is in direct fixed proportion to the angular movement of said rotary driving means; 'said impeller having a series of angularly spaced vanes struck from the impeller and all similarly inclined for permitting passage of fluid past the impeller and for substantially reducing viscous drag on the impeller as the impeller is moved in said one direction.

References Cited in the file of this patent UNITED STATES PATENTS 

